The improvement relates to a device for linear measurement of a hot work piece to be separated by a torch-cutting machine, consisting of a water-cooled measuring roller, which is provided with a transmitter, determining the measuring length and connected with a control device of the torch-cutting machine.
It is known to use measuring rollers - water-cooled as a rule - for the measuring of the length of a work piece or a partial piece. In such practice the circumference of the measuring roller, rolling on the work piece, is utilized for the determination of the work piece length. Since in measuring, the measuring roller comes to abut directly the hot work piece, often still glowing or red hot, it is necessary to cool the measuring roller so that the roller diameter does not change due to the temperature influence (of the hot work piece), something which otherwise would lead to fault measurements.
In a measuring device (DT-OS 2,315,865) of the prior art, a measuring roller washed by coolant is employed. In this known embodiment, a coolant supply conduit ends laterally (in the area of the hub) in the measuring roller. This conduit is coaxially enveloped by a further conduit in the annular chamber (formed by this conduit and the coolant supply conduit) of which the "heated" coolant is again drawn off from the measuring roller in the form of a closed cycle. The bearing of the measuring roller takes place still in the area of the work piece so that additional cooling of the bearing point is required.
In addition, it is indispensably required to maintain tight the water supply and discharge, since otherwise a local cooling would set in due to the emerging water, something which results in a structural change in this work piece area.